Wednesday, March 04, 2009

Foo

Seriously. Foo! I have worked with phantasmajector-based[1] stardrive finals for what, fifteen years now? Just about. And the blame widgets still act up in ways that defy all logic and reason.

The most-needed part I didn't have yesterday -- an ultrahigh voltage wiring harness that tends to burn out, and shame on me for not realizing I'd used the last ready spare a month ago -- showed up this morning while I was showering. Handsome Dave is on the Earlybird rotation for the middle watch[2] and called me in my quarters. Just as well, I was about done anyway. Wrapped up in a towel, leaned out the washroom door, and punched the Sound Only button, leaving the camera, thank you, off:

"Please Leave A Message After The Tone."

"You don't fool me with that, Bobbi."

"Aw, rats! --C. Jay hung up and redialed when I did it to him."

"Ha! HV umbilical's here; the Chief wants me to check out the controls for the hull cam at the Drive mast anyway, so I'll run this up myself and lend a hand with the B final, too."

"I'm on at 10:00, right?"

"Yepper. Seeya then!"

My quarters are about halfway between the control area with the Bridge, Drive Control, our Shop, etc. (it's centered on the five-mile width of the USAS Lupine and two miles in from the leading edge) and the Drive Room, eight miles back at the tapered trailing edge. The central maintenance tunnel our (and other departments) goofy "golf carts" run inside of isn't too easy to get to, though -- nearest accesses my keys will open are near the ends. So I was gonna hafta gulp breakfast quick and hit the slidewalk, and even then, he'd be there ahead of me.

* * * *

Which he was, sitting in the workroom that is the front compartment of the Drive Room with the unshipped camera control box open on the bench and holding a highly-prohibited cigarette cupped in one hand, near the solder-vapor inhaler. He looked up in mild guilt, but as he doesn't smoke much and is careful about it, I ignore it; there are designated smoking places on the ship but none near the Drive Room.

"What's the deal with the tube?"

"Y'got me, Dave. Ran for a couple hours yesterday, then shut down right as I was leaving -- on OT! -- and kept on crowbarring no matter what I tried. I want to bring it up with no drive, see if we've got a shorted tube or what."

No sooner said than done -- I went back to the stardrive final amplifiers, killed the driver amplifier breakers for B, and started the warm-up cycle, to STANDBY from BACK HEAT. Five minutes, so I went back to the work room and had a look at the well-worn and much-repaired control box while it warmed up and Dave finished his illicit luxury.

"Up here, this thing goes nuts when the control modem is running," Dave said. "Took it down to Engineering and it worked fine on the bench. Not a glitch."

"Sounds like the Drive field is gettin' into it. --Oops, time."

We went back, I stared at the meters stuffed behind plex in the High Voltage section and he hit the switch. Bam! came up, shut right down. The meters all jumped and dropped back to zero.

"Try 'er again."

Bam!

"Okay, OFF. Ten minutes to spool down, then we'll open up the grid cavity, yank the cathode-end connections, and see if it will come up with the tube disconnected. If so, dead tube. Expensive."

Dave nodded, "If not, shorted HV harness. PITA to change."

"Yeah."

Back to fiddling with the camera controls. Sure enough, hooked up, the thing runs amok, random control outputs. Good thing it's not connected to the camera!

I heard the high-pressure blower howl down the scale, and headed back to open up the grid cavity (five bolts. 36, 000 Volts. Will I use a grounding hook? Oh, yeah). It takes one small rotary switch that should shut the rig off even if I missed a step, one king-sized switch that shorts the HV (and you get to watch the contacts close though a plastic window -- I dread the day it's hot-switched), three circuit breakers and one lock-out bar before you can think about opening it up. It's anticlimactic from there, two small plugs and two fat ones to unplug, stand on tiptoe to reach in and stuff them down away from the connectors, then close it back up, open up the logic-and-control chassis and flip the TEST 1 switch to defeat the "tube okay" safety, flip the three breakers and two rotary switches, hit the STANDBY button and then it's five minutes to kill before the rig is in READY.

Back in the workroom, Dave had the modem subchassis pried loose and was looking at the soldered connections -- a through-hole PC board, how quaint -- with a bright light and magnifying glasses. "Does this look right to you?"

I leaned close and squinted, "Not so much. Kind of a cold joint there, and these look like the lead didn't wet, or it broke free--"

"Could that be it?"

"Worth a try, lets fire up the iron." I looked at my watch. "Tube's ready!"

Went back to the rig, hit the switch, and the high voltage came right up. Held. Thirty seconds. Shut it down and we looked at each other. If HV will come up with the tube disconnected but acts like there's a short when the tube is connected--

"That's not good."

"Could be costly. Let's try again." This time we ran it for a minute. Happy as a clam.

"Fine, " I said, "Darned if I'm gonna tell the Chief we need a new tube without triple-checking. This one's not five, no, six months old. When it's cycled back down, I'll hook the tube up and we'll try it again."

...And, this being a mildly perverse universe, when we did, it came up and ran. Parameters were a bit off, so I tweaked for the proper "idling" current and we applied drive. Rig came up. Produced power output. Ran for ten minutes, then BAM! Overload. Off.

Reset it and it shut right back down. But the heater voltage had crept way up. Reduced that to normal, a little less, turned the rig on, and it held; went out, worked on the camera control for half an hour and BAM! The B stardive final. Off.

We spent the next four hours, getting longer and longer runtimes, the settings getting farther and farther away from optimum, until it stayed up for two hours...three... and as far as I know, it's running now. Operating way, way off from what it should be, the heater voltage low, the grid bias cranked up, running too much grid current and too little collector current -- but running. By everything I know, it's Seriously Wrong, but it is running. And after eight and a half hours, that's good enough for me.

Foo.

The camera controller? Resoldered nearly everything and it stopped being flaky. I still have my doubts, but we're scheduling in some riggers (in use, it's a mounted bit too far out on too awkward a structure -- it takes specialists to deal with that) and we'll see what it does out near the Drive field projectors. Hopes are high!

* * * *
Emily, by the way, was not left out on the hull. While her suit mic -- both of them! -- didn't work, she could hear all right. The EVA tech did remember (eventually) to tell her the short Jump was off and her E&PP boss scrubbed the task she was on -- second shift finished up the solenoid valves in the graywater main with a proper crew of two, with working comms gear, well ahead of the reskedded Jump. I may write about that Jump in greater detail but let's just say it did involve some vector changes. Ugly ones. And guess whose helmet is red-tagged in the To Be Fixed cabinet in the Engineering Shop? Stencil says EMILY L. H'mmmmm.
_______________
1. Actually, L3's CEA is an oil-interphase phantasmatron, but close enough. It does the same thing at higher efficiency and, as you might notice, has some non-secret uses as well. Still, they are very careful to avoid using the right name for the thing.

2. It's complicated: Engineering (Maint., not Ops), Stores & Cargo, E&PP, and pretty much everyone who doesn't stand watch works a three-shift sked, 8 on, 16 off; most departments with critical functions stagger start times so there's constant overlap. Contrarily, operating positions stand traditional (merchant marine) watches: four on, eight off. Of course between Jumps, the Bridge crew can take it awfully easy; a lot of those chairs aren't occupied. Power Room, Enviro (the "E" of E &PP) and Drive Control always -- always! -- have somebody on watch in their individual Worry Seats, which are away from the bridge and from each other as a hedge against disaster. I've seen guys go as long as twelve hours on Drive Control, but only in emergencies. One end result of all schedule fiddle-faddling is, you interact with different people all the time. Even though the total population of the ship is pretty large -- subcontractors, merchants, passengers, etc. add up to small-town sized -- the workin' crew is around 400, few enough you can get a little sick of one another if you spent most your time with the third of 'em on your shift.

5 comments:

Turk Turon said...

Thanks!

charles said...

New email about Rose-Hulman rifle team sent to your email, please check.

Anonymous said...

Hey good going there charles.
There's two of us!
Thanks for giving a damn. Looking like a lost cause, though.

Jeff said...

You know, if I had to guess, I'd say you actually like your job.

Crucis said...

Back in the '30s and '40s, GE built some final amplifying tubes big enough that hatches were built into them to allow direct access to the elements. These tubes were amp in the range of 100,000 watts and up. Saw a picture of one once. The hatch was 10" x 14". Tube shell was hardened brass and aluminum, I think.